Latvia Reservoir Transparency

LVĢMC publishes water level readings (in centimetres above gauge zero) for a network of hydrological stations via the open-data portal data.gov.lv, under a CC0-1.0 licence. The 'Hidrometeoroloģiskie novērojumi' dataset provides 48-hour operational data and a 365-day rolling archive in CSV format without registration. However, no volumetric storage data (Mm³ or % fill) is published for any of Latvia's three Daugava cascade reservoirs (Pļaviņas ~509 Mm³, Ķegums, Rīga). The main data portal at meteo.lv redirects to a JOSSO authentication wall, making the interactive interface inaccessible without registration. Latvenergo, the state hydropower operator, publishes no real-time or historical reservoir level data; its online presence is limited to static educational content. ENTSO-E does not publish water reservoir data for Latvia because ENTSO-E reclassified Latvia's HPPs from 'Hydro Water Reservoir' to 'Hydro Run-of-river and poundage' in March 2015, removing them from the 16.1.D weekly reservoir reporting obligation. The net result is that current water levels must be inferred from river gauge readings at Daugava stations; no official source expresses current storage as a volume or percentage of capacity.

The data.gov.lv portal publishes LVĢMC hydrological datasets under CC0-1.0 as direct CSV file downloads — open format, no registration, no paywall. This represents a genuine open-data commitment. However, there is no REST API; datasets are static file downloads that must be re-fetched to stay current. The main LVĢMC interface at meteo.lv redirects every unauthenticated user to a login wall (JOSSO single sign-on), blocking direct access to the interactive data portal without an account. Longer historical data beyond the 365-day rolling archive on data.gov.lv appears to require a formal data request from LVĢMC or access through the authenticated portal. No Swagger or SPARQL endpoint has been identified. The GRDC (Global Runoff Data Centre) received an update of 32 Latvian discharge stations in September 2024, indicating that historical data is held internally by LVĢMC and is released on request rather than freely online.

Methodology v1.3.0 (capacity-weighted). Latvia's qualifying national reservoir capacity is approximately 509 hm³, concentrated in the Daugava cascade (Pļaviņas ~509 hm³, plus Ķegums and Rīga below threshold individually). LVĢMC publishes daily water-level readings in cm at hydrological stations on the Daugava via data.gov.lv (CC0-1.0, 48-hour operational window + 365-day rolling archive in CSV) — but no volumetric storage data and no stage-volume curve are published. Latvenergo publishes nothing operational, and ENTSO-E reclassified Latvia's HPPs as 'run-of-river and poundage' in 2015, removing them from 16.1.D weekly reservoir reporting. Covered capacity is 0 hm³. Coverage = round(100 × 0 / 509) = 0.

LVĢMC holds long hydrological records — ice observations on the Daugava at Daugavpils date to 1880, and discharge studies have used records from the 1950s onward (30 stations, 1950/51–2021/22 analysed in peer-reviewed literature). In September 2024, LVĢMC supplied daily discharge data for 32 stations to the Global Runoff Data Centre (GRDC), demonstrating that multi-decade machine-readable archives exist. However, the data.gov.lv open portal provides only a 365-day rolling archive in CSV. Access to data beyond one year appears to require registration on meteo.lv or a formal data request to LVĢMC. There is no confirmed free, machine-readable public archive extending beyond 12 months for the Daugava gauge stations. Hydrological yearbooks or comparable long-form public publications do not appear to be digitally archived in open-access format. The historical depth is real but not freely accessible online to the general public.

The LVĢMC 'Hidrometeoroloģiskie novērojumi' dataset on data.gov.lv is updated continuously (labelled 'constantly' on the portal), with the operational resource providing readings for the last 48 hours. The portal metadata shows the dataset was last updated on 2026-05-28, confirming active maintenance. LVĢMC's hydrological monitoring network includes automatic stations that presumably record at sub-hourly intervals, consistent with EU flood-warning obligations and Latvia's participation in EU flood risk management. The 48-hour publicly accessible window is narrow but is refreshed continuously, meaning the data is near-real-time even if the public archive window is short. Latvenergo does not publish any real-time reservoir data. The score is constrained by the fact that update frequency applies to water level proxies, not storage volumes, and the interactive meteo.lv portal (which may show more granular or real-time data) is gated behind registration.

LVĢMC is Latvia's designated authority under the WMO and implements international conventions on hydrology and meteorology, implying adherence to WMO measurement standards for river gauging. The centre participates in EU INSPIRE-compliant geospatial data sharing and has collaborated on multiple EU-funded research projects (ICEREG, TRANSWAT, ECOFLOW) where measurement methodologies are described in project reports. The data.gov.lv dataset page provides station metadata files (CSV) listing coordinates, parameters, and codes. However, there is no publicly accessible consolidated methodology document for how Daugava water level measurements are conducted, calibrated, or quality-controlled. No stage-volume relationship or bathymetric survey is published for the HPP reservoirs. Latvenergo does not publish operational parameters for its turbine head or reservoir management. Methodological information must be pieced together from EU project deliverables and academic literature rather than a dedicated public methods page.

The data.gov.lv open portal has a functioning English-language interface, and the LVĢMC organisation page lists datasets in both Latvian and English. The main LVĢMC corporate site (videscentrs.lvgmc.lv) is primarily in Latvian but the Wikipedia-linked institutional profile describes services in English. The authenticated meteo.lv data portal, which is the richer interface, shows at least a partial English section for its data search page (/en/hidrologija-datu-meklesana/). The CSV files themselves use Latvian column headers and Latvian station names without English equivalents. No English-language documentation exists for interpreting the gauge data in the context of reservoir storage. The ENTSO-E Transparency Platform, which would be an English-language international source for Latvian hydro data, does not publish reservoir data for Latvia following the 2015 reclassification. On balance, an international researcher can discover and download the raw CSV files through the English-language data.gov.lv portal but would encounter Latvian-only labelling and no English methodology documentation for contextualising the data.